Analog and memory integrated circuits have gained wide acceptance and utility in present day technologies, and the use of capacitors in these integrated circuits is almost universal. A typical integrated circuit will often include a metal-insulator-metal (MIM) capacitor, also interchangeably referred to as a metal-oxide-metal (MOM) capacitor. MIM capacitors are desirable because they have capacitor plates that are not subject to depletion. Consequently these capacitors have a low voltage coefficient. Additionally, MIM capacitors advantageously have a low temperature coefficient and excellent linearity.
MIM capacitors have also gained wide acceptance because they can be easily integrated into existing semiconductor device fabrication schemes. In many process flows, MIM capacitors are manufactured on the same level and in conjunction with the manufacture of active devices. That is, the component parts of the MIM capacitor and active device are manufactured in the same processing step. As an example, source, drain and gate electrodes in nMOS and pMOS transistors, and the first plate of the MOM capacitor, are often made from the same metal layer, provided in a blanket deposition step. Although the manufacture of active devices and MIM capacitor components in an integrated fashion is desirable, the performance characteristics of the MIM capacitor can suffer. In particular, it has been found that the leakage current of the MIM capacitor is unacceptably high, thereby limiting its use in many device applications or reducing yields of devices having acceptable operating characteristics.
Accordingly, what is needed in the art is a MIM capacitor and method of manufacture thereof that does not suffer from the disadvantages associated with conventionally manufactured MIM capacitors, as discussed above.